because
Joshua 22:8
And he spake unto them, saying, Return with much riches unto your tents, and with very much cattle, with silver, and with gold, and with brass, and with iron, and with very much raiment: divide the spoil of your enemies with your brethren.
Joshua 22:9
And the children of Reuben and the children of Gad and the half tribe of Manasseh returned, and departed from the children of Israel out of Shiloh, which is in the land of Canaan, to go unto the country of Gilead, to the land of their possession, whereof they were possessed, according to the word of the LORD by the hand of Moses.